Unsure of how to move forward with 81 EFI Imperial

[fury fan]

Swapping to a carb would be the first way to get this car drivable and determine if it's worth further investment.

Depending on your fab ability, a 90s Jeep Cherokee might have 3.73-ish gears and be in a suitable width for the Imp. Might need to move some perches or somethign.
Couple that with an A500 OD trans and you have a perky drivetrain.
Anything you put in front of it (even the stock engine) will give you a nice-driving car that should be fair on gas.

I would NOT NOT NOT use that EFI system pictured above. Those big/tall runners and large TB will not be very friendly on a low-CR / low-performance 318.
EFI can smooth a lot of sins, but it's not going to perform well on such a parts mismatch like that.

If going to EFI is truly desired, this car might be a good candidate for Howell EFI. They tweak throttle-body-era GM ECUs to other engines.
The GM system was stone-reliable, and that should be a high priority for an Imperial.
Universal TBI Kits Archives

Or the smaller-HP FiTech systems might be worth a look.

 

[kmccabe56]

ONE of the quirks of those EFI systems is that if the TOP of the air cleaner is removed, the mass air flow sensor loses it's signal. So with no signal of air flow through it, the computer thinks the engine has died, so no fuel delivery. MOST people who worked on or traded-for those cars knew of this situation.

Which is why the band clamp around the outer edge of the top of the air cleaner assy, to keep things sealed up so the mass air flow sensor, which is located IN THE SNORKEL of the air cleaner gets a solid air flow "into the engine" signal. Even a cock-eyed/crooked clamped top could result in enough "leakage" from the imperfect top seal to result in flaky running.

In looking at the system, it was hastily-designed by Chrysler Aerospace and configured to have minimal impact on assy line procedures and related costs. In that respect, the system can be installed just like a normal carburetor engine, in many respects, as the bulk of the EFI sensors and such are on the air cleaner base (termed "fuel plate" by Chrysler). It was more of a forced-marketing situation as Lincoln and Cadillac had their own EFI systems, so if Imperial was going to compete, they needed one too.

Going forward . . . it would seem that something like the Holley Sniper EFI family could provide a less-cumbersome system than any OEM EFI back then. Might be able to use the existing fuel supply system and adapt the Holley system to it? They now have 2bbl Snipers, which could be bolt-on situations rather than going to one of their 4bbl systems. This would keep the original "intent" of the car, too, just need a normal Chrysler 400 2bbl air cleaner, painted silver to complete the conversion.

On the cars which were converted to a (basically) Dodge Mirada/Chrysler Cordoba fuel system, some functions on the instrument cluster displays were rendered useless.

Those Imperials had some awfully-high-geared rear axle ratio (2.2?), so any thought of "high performance" is not applicable, but solid, smooth, and economical (but slow) performance can be. Especially when combined with their 5.2L V-8 and 4000lbs.

Just some thoughts,
CBODY67

Recently found the letter Chrysler sent to the dealers on converting an EFI Imperial to a carburetor. Along with a different fuel tank, sending unit, carburetor, aircleaner, wiring harness and other assorted bits, there was also a DIFFERENT instrument cluster. Conversion time was clocked at 18 hours. All at customer expense.

 

[CHARLES374]

Recently found the letter Chrysler sent to the dealers on converting an EFI Imperial to a carburetor. Along with a different fuel tank, sending unit, carburetor, aircleaner, wiring harness and other assorted bits, there was also a DIFFERENT instrument cluster. Conversion time was clocked at 18 hours. All at customer expense.

Customer expense ?

 

[70bigblockdodge]

Customer expense ?

It was at Chryslers expense.

 

[Jimmy Jippy]

You said it started no problem but now requires fuel to be dribbled in. How long did it run before this new problem developed? The hole in the tank, has that been taken care of? What is the condition of the tank (debris getting into EFI system)? What is the fuel pressure up top with key on?

While the quick answer would be "switch to carb!", maybe you can get it to run with the EFI.. I would give it a shot.

It always ran but only when gas was dribbled in, it has no gas tank as the previous owner somehow got a hole in the OEM tank and they took it off and threw it out! I'm not having EFI issues, just a fuel issue. the rest was just asking if I should stick with my EFI setup or just switch over to a carb. I'm also having my concerns with a fuel cell because I don't think the pressure will be proper, unless I maybe get an inline fuel pump

 

[Jimmy Jippy]

My take on the OPs post is that the EFI works fine but there is a hole in the gas tank. Weld up the hole and run it.

unfortunately the gentleman I purchased from tossed the old tank that had a hole rotted thru, sorry for any confusion

 

[70bigblockdodge]

Like I think I mentioned earlier a Volare, 2nd gen Cordoba, Mirada tank will go in the car. I have not pulled mine yet to see what exactly the difference is. I'm going to hook a modern pump with roughly the same values as the original. I have no intention of running it this way long term, just to satisfy my curiosity and see if the system still works since it is complete.

 

[300K Man]

Like I think I mentioned earlier a Volare, 2nd gen Cordoba, Mirada tank will go in the car. I have not pulled mine yet to see what exactly the difference is. I'm going to hook a modern pump with roughly the same values as the original. I have no intention of running it this way long term, just to satisfy my curiosity and see if the system still works since it is complete.

it is just a Carter fuel pump used in many vehicles late 80 ford trucks and mustangs have the same part number , inline Carter pumps work as well

 

[CBODY67]

The KEY thing about the EFI fuel pumps of back then is the higher pressure AND flow rates. Most normal electric pumps can NOT meet those criteria, even the race-version fuel pumps. Getting one for the Holley Sniper EFI system can do it, though, as an inline pump.

What pressure specs did the factory pump need to meet?

CBODY67

 

[70bigblockdodge]

The KEY thing about the EFI fuel pumps of back then is the higher pressure AND flow rates. Most normal electric pumps can NOT meet those criteria, even the race-version fuel pumps. Getting one for the Holley Sniper EFI system can do it, though, as an inline pump.

What pressure specs did the factory pump need to meet?

CBODY67

Fuel pressure is 36 psi max I think. Pump I already own is 31 psi system pressure so I'm ballpark enough that it should operate it.

 

[fury fan]

A Walbro GSL392 and an adjustable regulator at the throttle body would be a simple/modern way to get a sufficient fuel supply. (albeit overkill for a 318)
But verify that PSI rating on the Chrysler stuff to make sure the regulator is capable. The 392 might overflow the TBI's regulator and allow pressure to creep upward.

The return could be plumbed into a standard Mirada/Doba tank via a bulkhead fitting into the fuel sender (location can be very tight/specific) or into a flat spot in the tank where the sender goes in.

Regardless of the location, a piece of line should go into the tank to return the fuel such that it doesn't simply fountain-spray into the tank. A good routing would take the returning fuel close to the bottom of the tank, parallel if possible, and aimed away from the inlet sock.

 

[CBODY67]

On other EFI TBI systems, until the fuel pump pressure reaches the minimum spec (56psi), the engine will just spin and spin if the pressure is even 1psi too low. As soon as it reaches the spec pressure, THEN the injectors start to work and the engine runs. Which is one way to determine of the fuel filter is clogged and/or the pump is getting weak . . . extended crank time. Not sure of the Chrysler system, though.

The current issue with the Chrysler system is finding a supply of good parts for repairs and such. Forty years after production ceased. Especially with only about three years of production. The reason for the huge retro-fit kit was because they did not work as well as they should have, or did not work as some perceived they should.

End result, dissatisfied customers and some who wanted refunds for "loss of value" with the EFI system removed. Removing the emblems was a part of the kit's instructions!

As mentioned, the mass air flow sensor is in the air cleaner/fuel plate snorkel. Unless air flows through the snorkel, the MAF sensor thinks the engine is stopped, so NO fuel to the system or fuel to the injector nozzles . . . period. Which is why the seal around the air cleaner top is extremely important to seal it against air flow intrusion! Which could very well have been ONE reason the systems were considered "bad" when they might not have been, in the first place.

In one respect, Chrysler had to have the system on their flagship vehicle to be competitive with the crude EFI systems that Ford and GM had back then. On the other hand, Chrysler's engineering should have been sound, but like other things Chrysler had done, the "general public mechanics" of the time did not understand it, even in the dealerships. Chrysler restricted sales of Imperials to only dealers who would purchase their computer diagnostic tool for the system, although some other dealers could broker their cars to smaller dealers.

It was intended that Imperial owners return to the selling Chrysler dealer for service. But with only such limited sales, apparently few did. Which put that EFI system in the class of other things Chrysler did, while designed well, but people trying to work on them did not understand (as it was nothing like Ford or GM did), so the unfortunate result was "more Chrysler junk".

In later years, trying to "rig" things can make things worse. But to upgrade the system to a Holley Sniper system, combining the two systems, can be a viable situation, I suspect. Especially since Holley now does 2bbl EFI units. That's my theory, anyway.

FWIW,
CBODY67

 

[CHARLES374]

On other EFI TBI systems, until the fuel pump pressure reaches the minimum spec (56psi), the engine will just spin and spin if the pressure is even 1psi too low. As soon as it reaches the spec pressure, THEN the injectors start to work and the engine runs. Which is one way to determine of the fuel filter is clogged and/or the pump is getting weak . . . extended crank time. Not sure of the Chrysler system, though.

The current issue with the Chrysler system is finding a supply of good parts for repairs and such. Forty years after production ceased. Especially with only about three years of production. The reason for the huge retro-fit kit was because they did not work as well as they should have, or did not work as some perceived they should.

End result, dissatisfied customers and some who wanted refunds for "loss of value" with the EFI system removed. Removing the emblems was a part of the kit's instructions!

As mentioned, the mass air flow sensor is in the air cleaner/fuel plate snorkel. Unless air flows through the snorkel, the MAF sensor thinks the engine is stopped, so NO fuel to the system or fuel to the injector nozzles . . . period. Which is why the seal around the air cleaner top is extremely important to seal it against air flow intrusion! Which could very well have been ONE reason the systems were considered "bad" when they might not have been, in the first place.

In one respect, Chrysler had to have the system on their flagship vehicle to be competitive with the crude EFI systems that Ford and GM had back then. On the other hand, Chrysler's engineering should have been sound, but like other things Chrysler had done, the "general public mechanics" of the time did not understand it, even in the dealerships. Chrysler restricted sales of Imperials to only dealers who would purchase their computer diagnostic tool for the system, although some other dealers could broker their cars to smaller dealers.

It was intended that Imperial owners return to the selling Chrysler dealer for service. But with only such limited sales, apparently few did. Which put that EFI system in the class of other things Chrysler did, while designed well, but people trying to work on them did not understand (as it was nothing like Ford or GM did), so the unfortunate result was "more Chrysler junk".

In later years, trying to "rig" things can make things worse. But to upgrade the system to a Holley Sniper system, combining the two systems, can be a viable situation, I suspect. Especially since Holley now does 2bbl EFI units. That's my theory, anyway.

FWIW,
CBODY67

What Ford/GM cars had F.I at this time ?

 

[CBODY67]

What Ford/GM cars had F.I at this time ?

Not across the board, but on selected high-level models. For Cadillac, it was optional on the 500CID cars in 1975 as an TBI system. Later to be expanded to the then-new Seville (with the Olds 350 V-8) and 425 CID DeVilles until 1979 model year. The Seville was the only one to receive EFI as standard equipment.

Lincoln introduced EFI on the 1980 models, along with a similar engine management system. Combined with smaller engine size, the then-new 4-spd OD automatic, this allowed Lincolns to increase their fuel economy a good bit over the prior model year (per Wikipedia).

 

[70bigblockdodge]

Not across the board, but on selected high-level models. For Cadillac, it was optional on the 500CID cars in 1975 as an TBI system. Later to be expanded to the then-new Seville (with the Olds 350 V-8) and 425 CID DeVilles until 1979 model year. The Seville was the only one to receive EFI as standard equipment.

Lincoln introduced EFI on the 1980 models, along with a similar engine management system. Combined with smaller engine size, the then-new 4-spd OD automatic, this allowed Lincolns to increase their fuel economy a good bit over the prior model year (per Wikipedia).

The 4100 Cadillac comes to mind ('82 I think) that system had a load of problems

 

[CBODY67]

The 4100 V-8 had many issues to start with, including an increased drain-back time for oil to return to the crankcase at oil change time. Not to forget that the cam carrier was not a machined part of the cyl block. But as with all things GM, they eventually got those things figured out as the engine grew in size to 5.0L in later years.

IF Chrysler has tried to do such things, it would have been front page news when they failed. But for GM, "normal".

 

[70bigblockdodge]

On other EFI TBI systems, until the fuel pump pressure reaches the minimum spec (56psi), the engine will just spin and spin if the pressure is even 1psi too low. As soon as it reaches the spec pressure, THEN the injectors start to work and the engine runs. Which is one way to determine of the fuel filter is clogged and/or the pump is getting weak . . . extended crank time. Not sure of the Chrysler system, though.

The current issue with the Chrysler system is finding a supply of good parts for repairs and such. Forty years after production ceased. Especially with only about three years of production. The reason for the huge retro-fit kit was because they did not work as well as they should have, or did not work as some perceived they should.

End result, dissatisfied customers and some who wanted refunds for "loss of value" with the EFI system removed. Removing the emblems was a part of the kit's instructions!

As mentioned, the mass air flow sensor is in the air cleaner/fuel plate snorkel. Unless air flows through the snorkel, the MAF sensor thinks the engine is stopped, so NO fuel to the system or fuel to the injector nozzles . . . period. Which is why the seal around the air cleaner top is extremely important to seal it against air flow intrusion! Which could very well have been ONE reason the systems were considered "bad" when they might not have been, in the first place.

In one respect, Chrysler had to have the system on their flagship vehicle to be competitive with the crude EFI systems that Ford and GM had back then. On the other hand, Chrysler's engineering should have been sound, but like other things Chrysler had done, the "general public mechanics" of the time did not understand it, even in the dealerships. Chrysler restricted sales of Imperials to only dealers who would purchase their computer diagnostic tool for the system, although some other dealers could broker their cars to smaller dealers.

It was intended that Imperial owners return to the selling Chrysler dealer for service. But with only such limited sales, apparently few did. Which put that EFI system in the class of other things Chrysler did, while designed well, but people trying to work on them did not understand (as it was nothing like Ford or GM did), so the unfortunate result was "more Chrysler junk".

In later years, trying to "rig" things can make things worse. But to upgrade the system to a Holley Sniper system, combining the two systems, can be a viable situation, I suspect. Especially since Holley now does 2bbl EFI units. That's my theory, anyway.

FWIW,
CBODY67

Part of the problem with the system is 2 fold. Chryslers insistence on the lean burn idea, which I am a proponent of. It worked, if you know it's on there and your in a fuel mileage quest. For Sally secretary she just wants the car to go. Second part of the problem is EPA, once they see the first iteration on full tilt lean they are not allowing it to be fattened up at all which would have improved its ability to recover. Instead it goes into a lean loop that the limited computer can't get out of. This is documented on a 400+ page emails early forum type group.
Maf sensor is better, but GM had more practical map sensor on its TBI unit. Which allows operation without hermetically sealed air filter housing.

 

[CBODY67]

Yes, there were several issues at play when the system was designed. One was Chrysler's on-going financial issues, I suspect, in the years leading up to the early 1980s. Which, to me, is why the system is pretty non-invasive rather than being something which could go many places on other vehicles. The GM TBI system was not terribly expensive and was a good transition into port fuel injection, which everybody knew was coming. By observation, their systems were very reliable and easy to repair, if needed. Easier to change an injector than change main jets in an AFB, for example. Or to replace a mixture control solenoid on an electronic QJet. BTAIM

In those times, too, the many things which were added to the TQuad to pass emissions was criminal. Which may have also been influenced by Carter's eventual demise? It just seemed "wrong" to use a QJet, to me. End result, not a good time for Chrysler Powertrain or Chrysler in general. But that was 40+ years ago with "period" technology. Things are better now and many options abound as to doing what could have been done back then, if it had been available. To use the current "state of the art" items, which means a modern self-learning EFI with full ignition control in the mix, too.

GM had an optional ignition system on some later '70s Oldsmobiles which was a quiet copy of the Chrysler Lean Burn System. Low installation rates and only for one model year or so. The few owners I talked to who had one of those cars noted its better fuel economy than their previous carbureted Oldsmobiles had had.

I like the idea and such behind the LBS. An interesting thing is that the computer on my '80 Newport 360 2bbl is "Electronic Spark Control", but is the same part number as a friend's '78 Cordoba 400 had on it.

In the early days of Holley's add-on TBI EFI system, a friend in the hot rod industry said he had a possible deal to buy a 4bbl and a 2bbl Holley system. The price was right and I bought the 2bbl kit. FULL kit with unterminated wiring harnesses, additional sensors, and the computer to fine-tune WOT (another computer was available to make the system full-computer controlled, which I should have bought then). I pulled it out and looked at it, then put it back in the box for future use. It's still there. Several years later, Chrysler was putting a similar TBI system on the Dodge Ram V-8s, as I recall, pre-Magnum LA motor.

Enjoy!
CBODY67

 

[70bigblockdodge]

I think they came with 8.25 rear.

My bad, I was trolling on F,M,J bodies and 7.25 seems to be consensus. Well I got mine up in the air, pulled the tank and got a decent look at rear, and it is a 8.25, so I was wrong. Seems my head was too fat or gas tank really low to get a proper look. It was full of a lot of brake parts and rotors. Doesn't really change the ratios except add a 2.45 in 8.25. I can't read my rotted tag. I have made a temp fuel system now I need to get it connected.

 

[fury fan]

FWIW, there was a 2.2 ratio available in the 8.25" also.